Refrigerating apparatus



June 8,1943.

F. W. GERARD REFRIGERATING. APPARATUS Filed m. 24,,1941

3 Sheets-Sheet 1 June8 ,1943. F; w. GERARD 2,321,137

. I REFRIGERATING APPm'i'Us s Sheet s-Shakl gnn+,+a

v Patented June 8, 1943 REFRIGERATING APPARATUS Frank W. Gerard,Oakwood, Ohio, assignor to GeneralMotors Corporation, Dayton, Ohio, a

corporation of Delaware Application January 24, 1941, Serial No. 375,824

' Y (Cl. 62-129) 1 Claim.

This invention relates to refrigerating apparatus and more particularlyto an improved method and apparatus for both cooling and dryingair.

It has long been recognized thatmoisture may be removed from the air byflowing the air in contact with. adeliquescent salt or a solutioncontaining such a salt. Solutions of lithium chloride; calcium chlorideor the like are commonly used for this purpose. However, chemical dryingsystems of this type have not been used extensively because of the factthat very cumbersome and expensive equipment has been necessary. Anotherreason for the lack of popularity of chemical drying systems is that ininany'applications cooling in addition to drying is required. It has notbeen considered practical as a general rule to provide achemi'cal dryingsystem in addition to a mechanical cooling system, since amechanicalcoolingsystem may be'designed-so as to A becapable of removing a largequantity of mois- Fig. 2 is a sectional view, with parts broken away,taken on the line 22 of Fig. 1;

Fig. 3 is a fragmentary sectional view taken on the line 33 of Fig. 2;

Fig. 4 is a sectional view taken on line 4-4 of Fig. 5 is a sectionalview taken on the line 5-5 of Fig. 2; a

Fig. 6 is a plan view. partly diagrammatic, showing the distributor forthe hygroscopic medium;

Fig. '7 is an enlarged fragmentary sectional view I taken on the line'I| of Fig. 6;

both systems in a single cabinet very little larger j than that requiredfor housing an ordinary mechanical refrigerating system. a

It is another object or this invention to provide.

a compact selfcontained' unit which is not only eflicient in operationbut also inexpensive to ufacture.

hereinafter. An air filter 29 ismounted in the J One object of thisinvention is to provide improved heat exchange coils which require aminimum amount of space.

One object of this invention is to provide an improved arrangement fordistributing 'a hygroscopic liquid over the outer surface of a heatexchange coil.

A further object of this invention is to provide a simplifiedarrangement for drying airby means of a hygroscopic medium and forregenerating the hygroscopic medium.

A further object of this invention is to provid an improved controlsystem for a combined cooling and drying system.-. n 1

' Further objects and advantages of the present invention willbeapparent from the following description, reference being had to theaccompanying drawings, wherein a preferred form of the present inventionis clearly shown.

In the drawings: I

Fig. lis an elevational view, with parts broken away, showing thearrangement within the main air conditioning cabinet;

the refrigerant evaporator 32.

character 20 designates an outer casing within the structure shown inwhich is mounted a complete mechanical refrigcrating system and chemicaldrying system.

Air to be conditioned enters the cabinet 20 through one or more inlets22 arranged adjacent the top of the cabinet 20. The number of inletsprovided is determined by the number of rooms from which air to beconditioned is withdrawn. The entering air flows downwardly through aduct 24 which communicates with a duct 28, which in turn directs the airthrough the drying unit 28 described duct 26 as shown in Fig. 2. The airflowing through the drying unit 28 discharges into the evaporatorchamber 30 within which is mounted Air leaving the evaporator chamber 30flows into the chamber 34 which communicates'with a pair of ducts 36(Fig.

2) leading to the main blower housing 4o. A centrifugal type of blower42 discharges the conditioned air into the duct 43 leading to the plenumchamber 44 from which the air discharges through one or more outletducts such as 46 shown in Figs.

liquid reuse one motor for operating both fans.

may be controlled by means of a conventionalrefrigerant flow regulatingvalve, such as 54, arranged in the liquid refrigerant line or it may becontrolled by means of a fixed restrictor. Themotor-compressor-condenser unit 52 is preferably of the type disclosedin the Gould Patent No. 2,205,138. Cooling water is supplied to the unit52 through the cooling water inlet 58 and is discharged through theoutlet 88.

Reference character 82 designates a sump within which a supply ofhygroscopic liquid 84 is provided. Any type of hygroscopic liquid may beused, but lithium chloride is preferably used since only a small amountof lithium chloride is required to absorb a large amount of moisture. Apump 88, driven by means of a motor 88, circulates hygroscopic mediumfrom the sump 84 through the pipe line 88 which, in turn. has one branchline I8 leading to the distributor 12 and a second branch line I4leading to the distributor I8. The hygroscopic solution supplied to thedistributor I2 is distributed onto the outer surfaces of the coolingcoil 88 arranged in the path of 'the air flowing through the drying unit28. The

details of the coil 88 and the means for distributing the hygroscopicmedium over the outer surfaces of the coil 88 is described in greaterdetail hereinafter. The hygroscopic medium flowing over the outersurfaces of the coil 88 is cooled thereby and serves to remove moisturefrom the air flowing.

thereover. The hygroscopic medium flowing over the outer surface of thecoil 88 collects in the sump 82 (Fig. 5) from whence it returns to themain sump 82, through the return line 84.

Cooling water is supplied to the distributor 88 of the cooling coil 88through the pipe line 88. The water leaving the coil 88 flows throughthe pipe line 88 which leads. to the heat interchanger 82, the purposeof which will he described hereinafter. The water leaves the heatinterchanger 82 through the outlet 84. In order that the water removedfrom the air may be dissipated from the hygroscopic solution, thatportion of the hygroscopic solution flowing through the line I4 entersthe distributor I8 which distributes the hygroscopic medium onto theflnned tube elements 88 which are supplied with a heating medium in themanner explained hereinafter. As shown in Fig. 2, the outlet 84 may beconnected to the water inlet 58 of the motor-compressor condenser unit52.

As shown in Fig. 4, the distributor I8 is provided with a. plurality ofdrain holes 88 from which the hygroscopic medium drips onto thefinned-tubing 88. Steam is supplied to the flnned tubes 88 through thesteam line I88 and the condensate from the steam discharges through theliquid line I82 in accordance with well-known steam heating practicewhich needs no further description. The flow of steam to the tubes 88intake I I2 of the fan I88 is located in the end wall of the shield H3which encloses three sides of the heated tubes 88. The fan I88discharges the moisture laden air through an outlet I I4 (Fig. 3). Thedistributor I8 is provided with an overflow pipe H8 (Fig.. 1) whichcommunicates with the return line I28 leading to the main sump 82. Thehygroscopic medium flowing over the outer surface of the finned tubes 88collects in the sump I22 from whence it enters the line I24 which alsocommunicates with the return line I28 leading to the sump 82. In ordedto partially cool the liquid flowing through the return line I28, thisliquid is caused to flow through the innerpassage of the heatinterchanger 82. The hygroscopic medium collected in the sump I22 isrelatively-warm and concentrated.

In Figs. 6, 7 and 8, I have shown detailed views of the bottom wall ofthe distributor I2. The distributor I2 is provided with a plurality ofapertures I28 through which'the various sections of coil 88 pass. Asshown in Fig. 7, the material adjacent each of the apertures I28 isdepressed as at I 28. A notch I38 is provided in each of the depressedportions adjacent the tube. This notch is of such a size as to allow thedesired quantity of hygroscopic medium to flow therethrough. Eachupright section of the coil 88 is provided with a spiral fin I82 whichis preferably in the form of a wire wrapped around the outer surface ofthe tubing. A similar wire-is wrapped around each of the tubes 88 of theheating element. In constructing the spiral fins I32, wire is formedinto the shape of a long coil spring. This coil is thereafter placedaround the outside of the tubing. One end of the wire is arc tack weldedto the tubing and the coiled portion of tates the spreading of thelithium chloride soluis controlled by the solenoid valve I4 located inthe line I88. A conventional steam trap I85 is provided in, the lineI82. .The hygroscopic medium flowing over the heated tubes 88 gives offa considerable quantity of water vapor. This vapor is removed from thecabinet along with the air circulated through the cabinet by the fanunit I88.

The fan I88 is arranged in the upper portion of the cabinet as shown inFigs. 2 and 3 and is driven by a motor I88. While I have shown twoseparate motors for operating the fans 42 and I88, it is within thepurview of this invention to ing II8 admits air into the main cabinet8d- An opention in a very thin fllm over the entire surface. This fllmalso inhibits corrosion of the zinc.

The return bends may be formed separate in accordance with anyconventional practice which need not be described since any oneskilledin the art is familiar with the formation of return bends on finned heatexchange coils. I

As shown in Fig. 9 of the drawings, a -thermostat I48 which ispreferably mounted within the conditioned space controls-the operationof the motor-compressor condenser unit 52. A humidostat-I42 controls theoperation of the pump mo-' tor 88, the steam valve I84 and the fan motorI 88.- The pump motor 88 i further controlled by the mercury contactswitches I44 and I45 operated v by the float I48 located in the sump 82.The arrangement of the switches I44 and I45 is such that the circuit tothe pump motor 88 is broken in the event that the amount of liquid inthe sump 82 becomes too great or too small. By virture of thisarrangement, a leak in the hygroscopic liquid circuit, or a failure ofthe regencrating apparatus would serve to automatically stop the pumpmotor 68.

A hydrometer I48 controls a pair of mercury contact switches I50 and I52arranged'in series with the fan motor I08 and the valve I04. Thearrangement of the switches I50 and I52 is such that the circuit throughthe switches is broken whenever the concentration falls below apredetermined low value or exceeds a predetermined high value. By virtueof the above described arrangement the hygroscopic liquid will bemaintained at the proper concentration at all times and in the eventthat the concentrating apparatus fails to function due to somemechanical failure, then the accumulation of excess water in thehygroscopic liquid will serve to break the circuit to the motor 118 andthe valve I06.

A plurality of manual switches have been provided. for individuallycontrolling the various electrical circuits as shown in Fig.9. SwitchI60 is provided for deenergizing the entire system. Switches I62 and I'Mcontrol the refrigerating apparatus 52 and the main blower motor 50, respectively. Switch I66 is in series with the humidostat I42, whereasswitches I68 and I control the elements 68, I04 and I00, as shown.

While the form of embodiment of the invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of the claim whichfollows.

What is claimed is as follows:

In combination, a cabinet, a-first air now passage in said cabinet, asecond air flow passage in said cabinet, 9. first cooling coil in saidfirst air flow passage, a second cooling coil in said first air flowpassage, a sump in said cabinet adapted to contain a hygroscopic liquid,means for spraying hygroscopic liquid from said sump over said firstcooling coil so as to cool said liquid and simultaneously cause saidliquid to remove moisfor flowing air through said second named passagein said cabinet so as to carry away the moisture liberated from thehygroscopic medium circulating over said regenerating coil, refrigerantliquefying means in said cabinet for sup plying refrigerant to saidsecond named cooling coil, said last named means including a water coilfor absorbing heat, and means for supplying cooling water'to said firstnamed coil and said' water coil in series.

- FRANK W. GERARD.

